"Besides size how do the Ohm Walsh 2000 and 3000 series differ?"
Size of the speaker/enclosure, size of the Walsh driver, and size of the room that the speaker is capable of producing full range sound in accordingly.
Larger rooms generally require larger speakers to achieve similar good results, especially in the lowest frequency range. All Walsh models in the line are designed to sound equally good in rooms of various sizes. No need to buy larger more expensive models if a smaller one fits the bill. That's a fairly unique aspect of the OHM Walsh line.
Size of the speaker/enclosure, size of the Walsh driver, and size of the room that the speaker is capable of producing full range sound in accordingly.
Larger rooms generally require larger speakers to achieve similar good results, especially in the lowest frequency range. All Walsh models in the line are designed to sound equally good in rooms of various sizes. No need to buy larger more expensive models if a smaller one fits the bill. That's a fairly unique aspect of the OHM Walsh line.